Nonwoven material is often used as a surface layer in absorbent products such as nappies, incontinence pads, sanitary towels and panty liners, etc. It is customary in this case to apply an image or decoration to the nonwoven material by thermal embossing. In conjunction with embossing, the fibres are compressed by an embossing stamp, and the image is produced as a depression. The use of thermal embossing means that a number of fibres are caused to melt and are damaged, which reduces the softness of the surface, and this in turn impairs the strength characteristics of the material. The embossed image will also be situated beneath the base level of the nonwoven material, which leads to the image being less readily visible.
Images or decorations in nonwoven material can also be produced by hydroentangling. This can be done, for example, by means of hydroentangling against an image transfer surface. A substrate web of fibres is laid on the image transfer surface, wherein the substrate web is hydroentangled, that is to say it is sprayed with jets of liquid. The image transfer surface can be in the form of a wire gauze or a plate that exhibits depressions and/or projections. The nonwoven material receives its image or decoration against the wire gauze or the plate by being formed respectively against depressions and projections with the help of jets of liquid, and the nonwoven material receives an image or a decoration on both sides. A method of this kind is described in WO 02/04729. A nonwoven material produced in this way exhibits certain shortcomings with regard to its use in absorbent products. A poor contact surface with subjacent material may make it more difficult to glue in place, for example.
Another method for hydroentangling is described in WO 03/083197, where a nonwoven material with protuberances is produced. In this case, a plastic gauze is used as the carrier device for a web of fibres when it is hydroentangled.
EP 625 602 describes a nonwoven material that is used as a surface material in absorbent products. This nonwoven material has been hydroentangled so that it exhibits depressions on one side. The depressions retain liquid, which is not good for the distribution of liquid.
When nonwoven material is used as a surface layer in absorbent products, the ability to receive fluid is a significant characteristic. It is also important that the product does not lie too closely against the wearer's skin.
Layers of nonwoven material should also be easy to apply in absorbent products.
The intention of the invention is to solve the above problems and to improve nonwoven material.